find the percent composition of cu₂s? %cu= 35.946 %s= 64.054 %cu= 67.987 %s= 32.013 %cu= 79.854 %s= 20.145

Answer

Explanation:

Step1: Calculate molar mass of (Cu_2S)

Molar mass of (Cu = 63.546\space g/mol), molar mass of (S=32.065\space g/mol). Molar mass of (Cu_2S=(2\times63.546)+32.065 = 127.092 + 32.065=159.157\space g/mol)

Step2: Calculate percent composition of (Cu)

Percent composition of (Cu=\frac{2\times63.546}{159.157}\times100=\frac{127.092}{159.157}\times100\approx67.987%)

Step3: Calculate percent composition of (S)

Percent composition of (S=\frac{32.065}{159.157}\times100\approx32.013%)

Answer:

(%Cu = 67.987), (%S=32.013) (the blue - colored option)